Detachable bit rock drill



Jan. 24, 1939. I c COOK 2,144,832

Filed July 22, 1

Patented Jan. 24, 1939 OFFICE nn'racnanmm'r noon mun. p Charles mom Cook. South Porcupine, Ontario,

. Canada Application July 22, 1938, Serial N0. 220,768

6 Claims. (Cl. 255-64) My invention relates to improvements tachable bit rock drills of the kind wherein the bit is detachably interlocked with the shank in deag'a-inst longitudinal displacement but is permitted lateral movement on the shank, and an object of the invention is to provide means for preventing such lateral movement of the the shank wherein the drill may be used as a starter drill which is impracticable where the bit is permitted the above referred to lateral ment.

bit on move- A further object is to devise means for looking the bit on the shank against, lateral movement which will entail no alteration whatsoever in the construction of either bit or shank, such means being detachably insertable into the water I hole in the bit and extending into the water passageway in the shank.

A still further object is to provide means for locking the bit on the shank against lateral movement which will be exceedingly simple, inexpensive and which can be easily applied and detached without the use of other than the ordinary tools in the possession of the miner.

sequently a special starter drill hasto be used.

- By my invention, no starter drill ,is necessary as the detachable bit drill as above referred to may be employed throughout the drilling tion.

With the above and other objects in view. which Openwill hereinafter appear as the specification proceeds, my invention consists of the construction and arrangement all as hereinafter more particularly described and illustrated in the accompanying drawing in which:-

Fig. 1 represents in elevation a typicaldetachable bit rock drill in which the bit is interlocked to the shank by means of a dovetail tongue preventing longitudinal displacement of the bit from the shank, said tongue being inserted transversethe dotted lines.

ly into a. dovetail slot in the shank and such. bit

being permitted lateral movement as indicated by Fig. 2 isa vertical section through the detachable bit rock drill as illustrated in Fig. 1 showing my means in place for preventing lateral ment of the bit on the shank.

move- Flg. 3 is a plan view thereof taken from the cutter end of the detachable bit, and

- Fig. 4 is a detail in plan of my pin constituting the means for preventing the lateral movement of l the bit on the shank. 5

Like characters of reference indicate corresponding partsin the different views ofthe drawins.

As illustrated, the detachable bit rock drill comprises a detachable bit I having a transverse l ton ue 2 of dovetail cross-section inserted sidewise in a slot 3 of correspondingly dovetail crosssection formed in the bit engaging end of the shank 4. A water passageway extends axially through the shank 4 and registers with an axial 1 water orifice 6 through the bit and its tongue which terminates in a cup-shaped extremity 1 from which radiate the-bit cutters. 4

In a detachable bit rock drill as constructed above, the bit I, while interlocked with the shank 2o 4 against longitudinal displacement, is free to move laterally as illustrated in dotted lines in Fig. 1 and consequently cannot be used as a starter drill. Its purpose .is for drilling the hole after the latter has been started by a speclal starter drill as then the bit I will be prevented from lateral movement by the wall of the hole being bored.

The use of an independent starter drill entails unnecessary complication in the drilling operation and while attempts have previously been made to make the drill as above described a universal one such, for'instance, byemploying spring plungers and other locking devices for holding the bit to the shank against such lateral movement, they have all failed either due to cost, complexity or their inability to stand up in service.

In order to overcome the above disadvantages and provide an efllcient locking device against lateral movement between bit and shank, I in- 40 sert detachable means from thecutter end of the bit through the waterorifice 6 into the water pas.- sag way 5. Such means may well comprise a pin" 8 normallyheld in place by friction between its surface and the walls of the orifice 6 and passageway 5. As illustrated, such pin 8 is made of spring steelbeing, therefore, resilient and is of the form of a cotter pin having a head 9 received into the cup 1. 1

By the use of the pin 8 any lateral movement between bit and shank is prevented and the rock drill may consequently be employed as a starter drill as well as a drill for boring the entire hole. when it is desired to remove the pin 8 in drilling or otherwise, it is only necessary to withdraw it as by means of a cotter pin puller, pliers or other suitable tool and the drill will be restored to its initial condition as illustrated in Fig. 1.

Although I have described and illustrated my invention as applied to a detachable bit rock drill having a dovetail connection between bit and shank it will be apparent that it may be employed with any drill of the type in which lateral movement between bit and shank is normally permitted.

What I claim as my invention is:

1. In a detachable bit rock drill of the type' wherein the bit while interlocked with the shank against. longitudinal displacement is permitted lateral movement, the combination with the bit having the usual cutters and an axial water orifice therethrough and a shank having an axial water passageway therethrough adapted to register with the water orifice of the bit, of integral resilient detachable means inserted into the water orifice of the bit and extending into the water passageway of the shank for locking bit and shank against relative lateral movement, said means held in position solely by the friction between its surface and the walls of the water orifice and passageway.

2. In a detachable bit rock drill of the type wherein the bit while interlocked with the shank against longitudinal displacement is permitted lateral movement, the combination with the bit having the usual cutters and an axial water orifice therethrough and a shank having an axial water passageway therethrough adapted to register with the water orifice of the bit, of a headed pin inserted into the water orifice of the bit from the cutter end thereof and extending into the water .passageway in the shank for locking bit and shank against relative lateral movement,

said headed pin being held in position solely by the friction between its surface and the walls of the water orifice and passageway.

3.-In a detachable bit rock drill of the type wherein the bit while interlocked with. the shank against longitudinal displacement is permitted lateral movement, the combination with the bit having the usual cutters and an axial water orifice therethrough and a shank having an axial resilient pin inserted into the water orifice of the bit from the cutter end thereof and extending into the water passageway in the shank for locking bit and shank against relative lateral movement, said headed resilient pin being held in position solely by the friction between its surface and the walls of the water orifice and passageway.

4. In a detachable bit rock drill of the -type wherein the bit while interlocked with the shank against. longitudinal displacement is permitted lateral movement, the combination with the bit having the usual cutters and an axial water orifice therethrough and a shank having an axial water passageway therethrough adapted to register with the water orifice of the bit, of a headed bifurcated resilient pin inserted into the water orifice of the bit from, the cutter end thereof an'd'exiending into the water passageway in the shank for locking bit and shank against relative lateral movement, said headed bifurcated resilient pin being held in position solely by the friction between its surface and the walls of the water orifice and passageway.

5. In a detachable bit rock drill of the type wherein a bit is provided with a diametrical tongue of dovetail cross-section with an axial water orifice therethrough insertable into a diametrical slot of dovetail cross-section in the end of a shank which has an axial water orifice therethrough adapted to register with the water orifice in the bit whereby the bit is detachably interlocked with the shank against longitudinal relative movement while permitting free lateral movement; an integrally formed resilient pin detachably inserted into the water orifice of the bit and extending into the water orifice in the shank for preventing relative lateral movement between bit and shank,. said'pin being held in place solely by the friction between its surface and the walls of the water orifices in the bit and shank.

-6. In a detachable bit rock drill of the type .whereina bit is provided with a diametrical tongue of dovetail cross-section with anaxial water orifice therethrough insertable into a diametrical slot of dovetail cross-section in the end of a shank which has an axial water orifice therethrough adapted to register with the water orifice in the bit whereby the bit is detachably inter- 

